Gynecomastia

Gynecomastia is hypertrophy of breast glandular tissue in males. It must be differentiated from pseudogynecomastia, which is increased breast fat, but no enlargement of breast glandular tissue.

Pathophysiology

During infancy and puberty, enlargement of the male breast is normal (physiologic gynecomastia). Enlargement is usually transient, bilateral, smooth, firm, and symmetrically distributed under the areola; breasts may be tender. Physiologic gynecomastia that develops during puberty usually resolves within about 6 mo to 2 yr. Similar changes may occur during old age and may be unilateral or bilateral. Most of the enlargement is due to proliferation of stroma, not of breast ducts. The mechanism is usually a decrease in androgen effect or an increase in estrogen effect (eg, decrease in androgen production, increase in estrogen production, androgen blockade, displacement of estrogen from sex-hormone binding globulin, androgen receptor defects).

Pearls & Pitfalls

During infancy and puberty, bilateral, symmetric, smooth, firm, and tender enlargement of breast tissue under the areola is normal.

If evaluation reveals no cause for gynecomastia, it is considered idiopathic. The cause may not be found because gynecomastia is physiologic or because there is no longer any evidence of the inciting event.

*Not all drugs that have been associated with gynecomastia have been shown to cause gynecomastia through challenge-rechallenge testing.

†Drugs are listed in order of frequency of association.

Evaluation

History:

History of present illness should help clarify the duration of breast enlargement, whether secondary sexual characteristics are fully developed, the relationship between onset of gynecomastia and puberty, and the presence of any genital symptoms (eg, decreased libido, erectile dysfunction) and breast symptoms (eg, pain, nipple discharge).

Review of systems should seek symptoms that suggest possible causes, such as

Past medical history should address disorders that can cause gynecomastia and include a history of all prescribed and OTC drugs.

Physical examination:

Complete examination is done, including assessment of vital signs, skin, and general appearance. The neck is examined for goiter. The abdomen is examined for ascites, venous distention, and suspected adrenal masses. Development of secondary sexual characteristics (eg, the penis, pubic hair, and axillary hair) is assessed. The testes are examined for masses or atrophy.

The breasts are examined while patients are recumbent with their hands behind the head. Examiners bring their thumb and forefinger together from opposite sides of the nipple until they meet. Any nipple discharge is noted. Lumps are assessed and characterized in terms of location, consistency, fixation to underlying tissues, and skin changes. The axilla is examined for lymph node involvement in men who have breast lumps.

Red flags:

The following findings are of particular concern:

Localized or eccentric breast swelling, particularly with nipple discharge, fixation to the skin, or hard consistency

Interpretation of findings:

With pseudogynecomastia, the examiner feels no resistance between the thumb and forefinger until they meet at the nipple. In contrast, with gynecomastia, a rim of tissue > 0.5 cm in diameter surrounds the nipple symmetrically and is similar in consistency to the nipple itself. Breast cancer is suggested by swelling with any of the following characteristics:

Eccentric unilateral location

Firm or hard consistency

Fixation to skin or fascia

Nipple discharge

Skin dimpling

Nipple retraction

Axillary lymph node involvement

Gynecomastia in an adult that is of recent onset and causes pain is more often caused by a hormonal abnormality (eg, tumor, hypogonadism) or drugs. Other examination findings may also be helpful (see Table 4: Interpretation of Some Findings in Gynecomastia).

Testing:

If breast cancer is suspected, mammography should be done. If another disorder is suspected, appropriate testing should be done (see Table 2: Some Causes of Gynecomastia). Extensive testing is often unnecessary, especially for patients in whom the gynecomastia is chronic and detected only during physical examination. Because hypogonadism is somewhat common with aging, some authorities recommend measuring the serum testosterone level in older men, particularly if other findings suggest hypogonadism. However, in adults with recent onset of painful gynecomastia without a drug or evident pathologic cause, measurement of serum levels of LH, FSH, testosterone, estradiol, and human chorionic gonadotropin (hCG) are recommended. Patients with physiologic or idiopathic gynecomastia are evaluated again in 6 mo.

Treatment

In most cases, no specific treatment is needed because gynecomastia usually remits spontaneously or disappears after any causative drug (except perhaps anabolic steroids) is stopped or underlying disorder is treated. Some clinicians try tamoxifenSome Brand NamesNOLVADEXClick for Drug Monograph 10 mg po bid if pain and tenderness are very troublesome in men or adolescents, but this treatment is not always effective. TamoxifenSome Brand NamesNOLVADEXClick for Drug Monograph may also help prevent gynecomastia in men being treated with high-dose antiandrogen (eg, bicalutamideSome Brand NamesCASODEXClick for Drug Monograph) therapy for prostate cancer; breast radiation therapy is an alternative. Resolution of gynecomastia is unlikely after 12 mo. Thus, after 12 mo, if cosmetic appearance is unacceptable, surgical removal of excess breast tissue (eg, suction lipectomy alone or with cosmetic surgery) may be used.

Key Points

Gynecomastia must be differentiated from increased fat tissue in the breast.

Gynecomastia is often physiologic or idiopathic.

A wide variety of drugs can cause gynecomastia.

Patients should be evaluated for clinically suspected genital or systemic disorders.